class Student {
  String _name; //使用_开头的属性为私有属性 私有属性已下划线开头与Pythony一致;
  int _age;
  double _height;
  double _weight;

  Student(this._name, this._age, this._height, this._weight);
  void show() {
    print("Name: $_name, Age: $_age, Height: $_height, Weight: $_weight");
  }

  void eat() {
    print("$_name is eating");
  }

  void sleep() {
    print("$_name is sleeping");
  }

  void study() {
    print("$_name is studying");
  }

  void showBMI() {
    double bmi = _weight / (_height * _height);
    print("BMI: $bmi");
  }

  void showGrade() {
    if (_age >= 18) {
      print("$_name is an adult");
    } else {
      print("$_name is a minor");
    }
  }

  void showAge() {
    print("$_name is $_age years old");
  }

  void showHeight() {
    print("$_name is $_height cm tall");
  }

  void showWeight() {
    print("$_name weighs $_weight kg");
  }

  void showName() {
    print("$_name");
  }
}
